5w30 vs 10w30: Top Engine Oil Facts You Need To Know

Oil is the fuel of every motor. Without it, you won’t be able to explore the great outdoors or venture into the wilderness. When it comes to engine oils for your motorhome and RV, you have a variety to choose from.

That includes the two popular types, the 5w-30 and 10w-30. Each oil type has its own strengths and weaknesses. Hence, we’ll be conducting a showdown between the both of them – 5w30 vs. 10w30.

Now, before comparing the two and weighing which one is better, you should first know that several factors come into play when choosing an appropriate engine oil. That includes the external environment, driving conditions, the total engine mileage, and the manufacturer’s recommendation.

To start off, let’s know more about “engine oils”. Car lovers and mechanics are well aware what engine oils are and what they can do, but for typical riders like us, we may look at engine oils only at the surface level -- just as fancy gasoline types.

What Is An Engine Oil?​

Engine or motor oils are "lubricants", basically. They ensure that the moving engine parts don’t collide or rub with each other. If your engine lacks a lubricant, the parts will most likely stop working and acquire damages.​

When that happens, you have to consult with your mechanic regarding rebuilding or replacing the engine.

Moreover, motor oils contain corrosion or rust inhibitors to prevent engine rusting and it also cleans the engine of sludge.

Explaining The Numbers​

Almost all passenger vehicles today use multi-grade oils like 5w30 and 10w30. Have you ever wondered what does 5w30 or 10w30 mean? Are they just random figures manufacturers use to label motor oils?

First off, both oil types are designed to perform within the range of average and cold temperatures without sacrificing performance.

Actually, the terms "5w30" and "10w30" are termed as "viscosity grades". The first number in the viscosity grade is the low temperature (i.e. 5 or 10), while the "w" stands for winter.​

The number indicated in the low-temperature rating tells how fast and smooth the engine will start during cold temperatures. Generally, the lower the number, the less the oil thickens and subsequently, the easier the engine starts. So, 5w30 motor oils thicken less during the cold than a 10W30.

With regards to viscosity, multigrade oils are carefully designed to be thin during cold temperatures so the engine gets the protection it needs while it is still warming up.

On the other hand, the second number in the viscosity grade indicates the high-temperature rating (i.e. 30). This rating simply tells that a certain oil type is formulated to withstand "summertime" temperatures.​

Deciding Between 5w30 And 10w30 Motor Oils​

Temperature Setting

The first thing to take into account when trying to decide between 5w30 and 10w30 is the climate of the area where you live in.

For places with ambient temperatures reaching as low as -30°C (-22°F), 5w30 oil is your best bet. It’s the ideal choice if you live in colder climates such as the Northern United States or Canada.

Likewise, 5w30 makes an excellent choice in warmer climates that reach up to 35°C or 95°F. Generally, the 5w30 oil type can meet the demands of both hot and cold climates.

An engine in a colder climate would benefit from a 5w viscosity because, in this temperature range, the motor oil tends to thicken. On the other hand, a car in Death Valley would need perhaps a 10w viscosity to keep the oil from thinning out so much.

There’s even a15w40 motor oil formulated for tropical areas where temperatures are consistently high but never gets near freezing.

Intended Use

When it comes to driving around places with colder climates, the 5w-30 type is the way to go since it can give better engine protection and it flows better in the cold.

However, when operating in hot climates, engaging in frequent city driving (stop and go), and hauling heavy loads, vehicles should opt for the 10w-30 oil type.​

Vehicle Manufacturer’s Recommendation

More than the climate you’re in and your motor’s intended use, you should always use the engine oil weight recommended by your vehicle’s manufacturer because they know best.

Following their recommendations will surely provide your engine with the best protection and maximum fuel economy.

If you used a 10w-30 oil on a 5w30-designed engine, the high viscosity input may likely result in excessive temperatures and increased drag, whereas using a low-viscosity oil may cause that it to fly off and scatter among the engine’s internal components when in motion, leading to unnecessary contact that will accelerate engine wear.

With that being said, most automakers specify a range of oils compatible with specific motors, letting you choose the best engine oil that will fit your driving conditions.​

Are Thicker (High Viscosity) Oils Better?

First of all, let’s debunk the myth that thicker oils are better. Early engine oil versions are made thicker but through constant engine innovations, oil viscosities have gotten thinner due to the smaller bearing clearances.

Thicker oils tend to interfere with oil flow, causing oil pressure to increase. It may be alright to use high viscosity oils in a worn out engine because of the larger bearing clearances but for recent engine models, it may not be the best idea.

5w30 vs. 10w30: Which Is Better?​

Surprise, surprise! Both engine oils are great. You just have to know which is suitable for what.

Again, the 5w30 type is great multigrade oil usually used in low temperatures (i.e. winter) as well as high summer temperatures. Moreover, it’s fuel efficient since it imparts less drag on the engine’s moving parts and bearings.

On the other hand, the 10w30 type is thicker and may offer a better sealing capability for older engines since their clearances widen, requiring thicker oil for better protection.

All the factors aside, the most important thing to consider when choosing a good engine oil is to consult with your engine’s user manual.

Oh, hey! We almost forgot! Have you got any old motor oil stuck in your garage? Don’t discard it yet – it still has a ton of uses. Check out its potential uses in the video clip below.​

Hey there! Do you think you're using the right engine oil? Do you want to add some tips or more information about engine oils? Feel free to comment your thoughts below! Don't forget to share this post too. Cheers!

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